dunlap



. (No Model.)

L. E. DUNLAP. `sTYLOGMPHIG PEN.

No. 808144. Patented Nouv.. 18, 1884.

UNITED STATES PATENT OFFICE.

LOUIS DUNLAROF BOSTON, ASSIGNOR OF ONE-HALF TO HERBERT W. THAYER, OF FRANKLIN, MASSACHUSETTS.

STYLOGRAPHIC PEN.

SPECIFICATION forming part of Letters Patent No. 308,144-, dated November 18, 1884.

Application tiled July 19, 1884. (No model.)

To all whom it may concern,.-

Be it known that I, LoUIs E. DUNLAP, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Stylographic Pens; and I doI hereby declare that the same are fully described in the following specification, and illustrated in the accompanying drawings.

My invention is an improvement in the construction of stylographic pens; and it consists in an improved spring for the purpose of holding and adjusting the needle, or metallic point in its proper position, and giving it the requisite yielding movement in writing. Heretofore in pens of this character it has been common to mount the needle in a spiral metallic spring, and these springs have been of gold wire, in order to avoid the corrosion to which base metals would be liable. These springs-have been secured upon the tip of the air-tube, or within a tube fitted tightly into the barrel of the point-section, and hence were lacking in adjustability. By my improvement the needle is rendered adjustable to the position desired by a spring action and independent of the air-tube, and the cost of construction is materially lessened.

My invention provides a compound spiral and slotted spring of hard rubber or other suitable material, constructed as represented in the drawings, in which- Figure 1 is a longitudinal section showing all the parts in position, and Fig. 2, an enlarged view of my compound spring-piece with needle.

S is the point-section, constructed in the usual manner, in which the spring-piece A, carrying the needle c, is inserted. Said spring-piece is made from a tube of hard rubber, or other suitable material, of a size corresponding to the interior of the point-section, but cut slightly tapering toward the point end for greater ease in insertion, and freedom of movement ofthe spring. Said tube or spring has at its posterior extremity a radial rib orfiiange, d, for greater strength and to facilitate handling. The anterior portion of said tube, and up to within about one-sixteenth of an inch of the point end, is cut spirally, so as to form a spring, E, Fig. 2, of

such resilience as to admit of a slight forward and backward movement of the needle c, which is firmly secured in the point end by a plug or by cement. Through the posterior portion of said tube is cut a-longitudinal slot, g, `continuous with the spiral slot e, forming another spring, h, acting in a direction transverse to the axis of the spiral spring E, and fitting closely to the interior of the point-section. The compression'of said spring h facilitates the insertion,adj ustment, and removal of the needle and its compound spring, and when in place its expansion holds the parts firmly in position for use.

The springpiece or needle-holder in my pen is entirely disconnected from the air-tube k, and may be removed without disturbing the latter. The lower end of the air-tube, when in position for use, lies within and encircled by the spring h, but does not touch it.

N o new adjustment of the air-tube can therefore become necessary on account of the wearing away y,of the needle by use, as in that case the needle-holder is simply pushed forward by the hand being held in its new position by the spring h, as before. The flow of ink from the reservoir Z is permitted by the usual venthole, m, opening into the air-tube in the upper end of the case, and is stopped by putting on the cap containing at its inner end a rubber cushion against which the point rests,

as in other stylographic pens.

I claim as my invention- 1. In a stylographic pen, the compound spring A, having at one end the spiral portion E and. at the other end the longitudinally-slotted portion h, for the purposes set forth.

2. In astylographicpen, a compound spring or needle-holder formed from a tube of hard rubber with a longitudinal slot through its posterior portion, and having said slot continued in a spiral direction nearly to the opposite end thereof, for the purposes set forth.

In testimony whereof I hereto affix my signature in presence of two witnesses.

LOUIS E. DUNLAP.

Witnesses:

ALDEN FRINK, E. A. PHELPs. 

